Squirrel-cage rotor for electric motors.



G. DUNN. SQUIRREL GAGE ROTOR FOR ELECTRIC MOTORS.

APPLICATION rum) APR.12. 1910.

1,013,753. I Patented Jan. 2, 1912.

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SQUIRREL CAGE ROTOR FOR ELECTRIC MOTORS.

APPLICATION FILED APRJZ 1910,

Patented Jan. 2, 1912.

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j A Home UNITED STA'IEZS PA TENT OFFICE.

GANO DUNN, OF EAST ORANGE, NEW JERSEY. ASSIGNOR TO CROCKER-VVHEELER COM- PANY, OF AMPERE, NEW JERSEY, A CORPORATION OF NEW JERSEY.

SQUIBREL-CAGE ROTOR FOB ELECTRIC MOTORS.

Specification of Letters Patent.

Application filed April 12. 1910.

Patented Jan. ,2, 1912.

Serial No. 554.941.

To all whom it may comma:

lie it known that l. (laxo l){l.\'N, a citizen of the United States of America. and a resident of East Orange. county oi Essex, and State of New Jersey, have invented certain new and useful improvements in Squirt-eh Cage Rotors for Electric Motors, of which the following is a specification.

This invention relates to the construction of the secondary element of the rotor of an induction motonin combination witlrthe rotor body.

The. object of the invention is to provide a formpt squirrel-cage construction for the secmulary element in which the electric flux is well distributed, which will run cool, in which the longitudinal conductor bars are interchangeable, and in which the ends are electrically connected by segments which atTord parallel paths for the current and in which the usual tendency of the current to concentrate in those portions of the end rings which lie nearest the core will be prevented and an even distribution of the electric flux will be insured.

A further object of the invention is to provide a construction in which all the segments may be alike and formed of sheet metal by punching and readily assembled.

In the accompanying two sheets of drawings, which form a part of. this application, Figure 1 is a side view showing one end of a rotor embodying my invention. Fig. "2 is a face view of the same. Fig. 3 is a section through one end of the rotor on the line ]IIIII of Fig. 2 embodying a moditied form of my invention. Fig. 4 is an edge view of one of the segments of the form of Figs. 1 and 53. Fig. 5 is a face view of the same. Fig. 6 is an edge view of the segment embodying a modified form of my invention of Fig. 3. Fig. 7 is a face. view of the same.

In the form shown in Figs. 1. 2. 4 and a rotor body consisting of laminated plates of iron A constitutes the magnetic core of the rotor for an induction motor and supports in perforations around its periphery, a series of straight copper conductor bars B B of uniform section throughout. The ends of the. bars project beyond the core. Helical semnents C C suitably formed by punching liave'openings whiclrtightly engage the ends of the bars. The segments are usually of sheet copper but I do not confine myself to this material as under certain conditions other materials, as brass. iron or ahuninmn. may be preferable. They are placed on the ends oi the bars obliquely and each electrically connects a nmuber (if adjoining bars. So far as possible the scgments are so distributed that the inner end oi each segment engages the same bar with the outer end ot' another segment. whole number of bars is often, though not ncessarily prime. and even when not, the number of bars which it is convenient to span by each segment, may not be a factor ol the whole number of bars. This, however. d es not involve the employment of segments of ditierent lengths as the necessary adjustment can be etl'ected by increasing the lap to two bars at some of the points of lapping. .Tbe segments are preferably spaced for ventilation. The spacing is preserved by slippin washers D 1) over the ends of the bars. these may be formed by cutting up a segment into small pieces, 0:16) of which inchul s one or two perforations. 'lhez c washers are preferably located at the bars where segments begin and end so as to supplement the ele trical connection between successive segments which is ati'orded by the bar in transferring the current from the segment ending on the outside to-tlie beginning of the-next segnent on the inside:

In the form shown in Figs. 3. (i and 7 the ends of the helical segments C C are shown flanged at Z) 7) forming wind-vanes wl iitrh by centrifugal action induce a rapid anaof air over the egnn-nts and their flanges to increase the cooling. Tn addition to ,t he ptntorations in the segments or receiving the ends of the conductor bars additional perforations e 1 may be provided to increase the electrical resistance and improve the starting torque. In assembling there is ditliculty on account of the overlap when putting on the last stgtiitllla and the difficulty is solved by sliding the bars endwise out of the way while setting these segments in place.

'hat I claim as new, and desire to secure by Letters Patent o the inited States, is-

1. In a squirrel-cage rotor adapted for use as the secondary element of an induction motor, the combination of a laminated core, conductor bars carried thereby, and a plurality of oblique overlapping segments, each havinp; openings which tightly engage T he I ferent amounts of overlap, substantially as described.

3. In a squirrel-cage rotor adapted for use as the seconda motor, the combination of a laminated core, conductor bars carried thereby, and a plurality of like oblique segments each havin o enings which tightly engage the ends 0 t e conductor bars and overlap ing with different amounts of overlap, su stant-ially as described.

4. In a squirrel-cage rotor adapted for use as the secondar element of an induction motor, the comb nation of a laminated core, conductor bar's carried thereby, and a plurality of oblique overlapping s aced se ments each havin openings which tight y enga the ends 0% the conductor bars, substantially as described.

5. In a squirrel-cage rotor adapted for use as the secondary element of an induction motor, the combination of a, laminated core, conductor bars carried thereby, and a plurality of oblique overlappin segments each having openin s, which tig t-ly engage the ends of the intermediate conductor bars which it spans, substantially as described.

6. In a squirrel-cage rotor adapted for use as the seoonda element of an induction motor, the combination of a laminated core, conductor bars carried thereby, and a plurality of oblique segments overla pin with different amounts of overlap an eac having openings which tightly en ge the ends of the intermediate conductor are which it spans, substantially as described.

7. In a. squirrel-cage rotor adapted for use as the secondary conductor bars carried thereby, and a pluelement of an induction element of an induction motor, the combmation of a laminated core,

rality of like oblique segments overla pin with different amounts of overlap an eacfi having openings which tightly engage the ends of the intermediate conductor bars which it spans, substantially as described.

8. In a squirrel-cage rotor adapted for use as the secondar element of an induction motor, the combination of a laminated core, conductor bars carried thereby, and a plurality of oblique overlapping spaced se ments each having openings which tight-y engage the ends of the intermediate conductor bars which it spans, substantially as described.

9. In a squirrel-cage rotor adapted for use as the secondar element of an induction motor, the combination of a laminated core, conductor bars carried thereby, a plurality of oblique overlap ing segments electrically connecting the en s of the conductor bars, and spacing washers located at points of overlap and electrically connecting the segments, substantially as described.

10. In a squirre -cage rotor adapted for use as the secondary element of an induction motor, the combination of a laminatedcore, conductor bars carried thereby, and a plurality of obli ue overlappin spaced segments clectrica ly connecting t e ends of the conductor bars, the segments having flanged ends forming wind-vanes, substantially as described.

11. In a squirrel-cage rotor adapted for use as the secondary element of an induction motor, the combination of a laminated core, conductor bars carried thereby, and a plurality of obli ue overlappin spaced segments electrica ly connecting t e ends of the conductor bars, the segments having flanged ends forming wind-vanes, and having perforations to increase their electrical resistance, substantially as described.

Signed at East Orange, N. J., this 9th day of April, 1910.

GANO DUNN.

Witnesses:

J. MACDONALD SMITH, H. C. Haamson. 

